如何从 Objective C 中的 NSData 十六进制值中按索引获取位值
How to get the Bit value by index from NSData Hex value in Objective C
我有 NSData 个 Hex
<80140142 0073ffff ffff04ff>
我可以通过索引
得到Byte值
NSData *commandIDData = [mqttResponseData subdataWithRange:NSMakeRange(3,1)];
<42> // 66
如何通过索引获取 Bit 值？
0100 0010
例如
index[0]=0
index[1]=1
index[2]=0
index[4]=0
NSData *statusData = [mqttResponseData subdataWithRange:NSMakeRange(3,1)];
const unsigned char *statusByte = [statusData bytes];//Hex<4F>/Decimal-79/Binary-01001111
for (int i = 0 ; i < 8; i++) {
bool chanelValue = [[NSNumber numberWithChar:(*statusByte >> i) & 0x01] boolValue];//i = 0 right most bit
NSLog(@"chanelValue %d: %d",i+1,chanelValue);//1 1 1 1 0 0 1 0
}
我有 NSData 个 Hex
<80140142 0073ffff ffff04ff>
我可以通过索引
得到Byte值
NSData *commandIDData = [mqttResponseData subdataWithRange:NSMakeRange(3,1)]; <42> // 66
如何通过索引获取 Bit 值？
0100 0010
例如
index[0]=0 index[1]=1
index[2]=0
index[4]=0
NSData *statusData = [mqttResponseData subdataWithRange:NSMakeRange(3,1)];
const unsigned char *statusByte = [statusData bytes];//Hex<4F>/Decimal-79/Binary-01001111
for (int i = 0 ; i < 8; i++) {
bool chanelValue = [[NSNumber numberWithChar:(*statusByte >> i) & 0x01] boolValue];//i = 0 right most bit
NSLog(@"chanelValue %d: %d",i+1,chanelValue);//1 1 1 1 0 0 1 0
}